Enhanced anaerobic digestion of post-hydrothermal liquefaction wastewater: Bio-methane production, carbon distribution and microbial metabolism

• Published in: The Science of the total environment Vol. 837; p. 155659
• Main Authors: Li, Ruirui, Liu, Dianlei, Zhang, Yuanhui, Tommaso, Giovana, Si, Buchun, Liu, Zhidan, Duan, Na
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2022
• Subjects: Anaerobic digestion; Chlorella; Metagenomic; Post-hydrothermal wastewater (PHWW); Total carbon; Up-flow anaerobic sludge bed reactor (UASB); Chlorella; Total carbon; Post-hydrothermal wastewater (PHWW); Metagenomic; Anaerobic digestion; Up-flow anaerobic sludge bed reactor (UASB)
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.155659

Hydrothermal liquefaction (HTL) is a cost-effective and environment-friendly technology for using biomass to produce bio-crude oil. The critical challenge of HTL is its complicated aqueous product containing high concentrations of organics and diverse toxicants. This paper reports the continuous anaerobic digestion of raw and zeolite-adsorbed Chlorella HTL wastewater using up-flow anaerobic sludge bed reactors. The bio-methane production capacity, total carbon distribution and microbial response were investigated. The anaerobic process was severely suppressed when more than 20% raw wastewater was fed; while it showed essentially improved performance till 60% pre-treated wastewater was added. Produced methane contained 17.3% of the total carbon in feedstock, which was comparable with the value (16.7%) when 25% of raw wastewater was added. The metagenomic analysis revealed distinct microbial community structures in different stages and feedstock shifts. The abundance of functional genes was consistent with anaerobic digester performance. [Display omitted] •Anaerobic digestion and zeolite adsorption were integrated for PHWW treatment.•Zeolite pre-treatment essentially promoted the degradability of PHWW.•Up to 60% of the adsorbed PHWW could be efficiently converted.•Microbial insights into biological process were unveiled via metagenomic sequencing.